Connector control system



Dec. 13, 1949 A. E. JOEL, JR

CONNECTOR CONTROL SYSTEM Filed D60. 51, 1946 15 Sheets-Sheet 1 Wow Hutk O .523 zit 2 56C EC wwwwwmwm GR flat at 1 E QGE :si 0 2m QGR not p but GR IE at Nut 22k A. fdEZS/e.

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ATTORNEV Dec. 13, 1949 I A. E. JOEL, JR 2 ,37

CONNECTOR CONTROL SYSTEM Filed Dec. 31, 1 946 15 Sheets-Sheet 2 T0 INTERRUPTER FRAME CK 7.

\ 1 TO MACH/NE RING/N6 //v|/ TOR A. E. OEL, JP. By

ATTORNEY A Dec. 13, 1949 A. E. JOEL, JR' 2,491,377

CONNECTOR CONTROL SYSTEM I Filed Dec. $1, 1946 15 Sheets-Shee 5 T0 INTERN/P FR CK T lNVENTOR BVA. E JOEL,JR.

ATTORNEY Dec. 13, 1949 A. E. JOEL, JR 2,491,377

' CONNECTOR CONTROL SYSTEM Filed Dec.- 31, 1946 15 Sheets-Sheet 4 J INTERMEDIATE GROUP INVENTOR A. EJOEL, JR.

ATTORNEY Dec. 13, 1949 ALE. JOEL, JR 2,491,377

CONNECTOR CONTROL SYSTEM Filed Dec. 31, 1946 15 Shets-Sheeti INK/EN TOR A. E. JOEL, JR.

FIGS

ATTORNEY Dec. 13, 1949 A. E. JOEL, JR 2,491,377

CONNECTOR CONTROL SYSTEM Filed Dec. 51, 1946 15 Sheets-Sheet e /A/ A. E. JR.

ATTORNEY Dec. 13, 1949 A. E. JOEL, JR 2,491,377

CONNECTOR CONTROL SYSTEM v Filed Dec. 31, 1946 I l5 Sheets-Sheet 7 g Q INVENTOR k 5 A. E. JOEL, JR.

Dec. 13, 1949 Filed Dec. 51, 1946 F/Gi 8 A. E. JOEL, JR

CONNECTOR CONTROL SYSTEM 15 Sheets-Sheet 8 lNl/ENTOR A. E. JOEL, JR. By

ATTORNEY Dec. 13, 1949 A. E. JOEL, JR 2,491,377

CONNECTOR CONTROL SYSTEM Filed Dec. 31, 1946 15 Shets-SheetQ EMERGENCY REGULAR /NI/ENITOR A. E. J0L,JR

ATTORNEY Dec. 13, 1949 A. E. JOEL, JR 2,491,377

CONNECTOR CONTROL SYSTEM File d Dec. 51, 1946 15 Sheets-Sheet 1O T0 Misc. ckr v v FOR TERM. FR.

6- Mali;

A TTORNE V Dec. 13, 1949 A. E. JOEL, JR 2,491,377

CONNECTOR CONTROL SYSTEM Filed Dec. 31, 1946 15 Sheets-Sheet ll INVENTOR A. E JOEL, JR.

ATTORNEY Dec. 13, 1949 A. E. JOELQJR 2,491,377

} CONNECTOR CONTROL SYSTEM Filed Dec. 31, 1946 15 Sheets-Sheet 12 IND. Ck 7.

k 3 '-/Nl EN7'OR A. E. JOEL, JR. BY k r a. Mm

A T TORNE V Dec. 13, 1949 A. E. JOEL, JR 2,491,377

CONNECTOR CONTROL SYSTEM Filed Dec. 31, 1946 15 Shets-Sheet 15 lA/I/E/VTOR By A. E.JOEL,JR.

ATTORNEY Dec. 13, 1949 A. E. JOEL, JR 2,491,377

CONNECTOR CONTROL SYSTEM Filed Dec. 31, 1946 15 Sheets-Sheet 14 ,INVENTOR 4.5. JOEL, JR.

ATTORNE V Dec. 13, 1949 A. E. JOEL, JR

CONNECTOR CONTROL SYSTEM Filed Dec. 51, 1946 15 Sheets-Sheet l5 .Q mik M/l EN 70/? A. 5.105 L, JR. Br

A TTOR/VEV l atented Dec. 13, 1949 CONNECTOR CONTROL SYSTEM Amos E. Joel, Jr., New York, N. Y., assignor to Bell Telephone Labor atories, Incorporated,

New York, N. Y., a corporation of New York Application December 31, 1946, Serial No. 719,354

18 Claims. 1

This invention relates to telephone systems and more particularly to systems employing common control circuits for operating automatic switches to extend telephone connections.

When interoffice calls are to be completed by such equipment, it has heretofore been customary to first connect an incoming trunk with one of a plurality of registering devices and then connect that registering device with one of a plurality of switch control circuits.

In accordance with the present invention, means is provided for connecting an incoming trunk directly with a switch control circuit.

Since such an arrangement requires the connection of any one of a large number of trunk circuits with a comparatively small number of control circuits the trunks are arranged in groups, each having an individual connector, and subgroups each having a connecting element in one connector, while the control circuits or markers have individual connecting elements in each connector.

More specifically, each connector comprises a plurality of multicontact relays, one for each trunk subgroup and one for each control circuit with a series of preference relays for the trunk groups and a series of preference relays forthe control circuits which determine the order in which the trunk subgroups may be served and the order in which the control circuits are available.

In accordance with a feature of the invention a set of auxiliary preference relays is provided for the trunk subgroups and for the control circuits with means for substituting these auxiliary preference relays for the regular preference relaysin any connector or in the various connectors in rotation.

In addition, means is provided in connection with the auxiliary preference relays to advance the preference with each use.

These and other features of the invention will be more clearly understood from a consideration of the following description read in connection with the drawing in which:

Figs. 1 to 3, inclusive, show an incoming trunk circuit;

Figs. 4 to 15 show the connector arrangement;

Fig. 4 showing the trunk preference relays;

Fig. 5 showing the trunk group multicontact relays;

Fig. 6 showing the marker multicontact relays;

Figs. 7 and 8 showing certain connector control circuits;

Fig. 9 showing the regular trunk group and marker preference relays;

Fig. 10 showing the connector preference relays;

Figs. 11 and 12 showing the emergency disconnect and cut-in relays;

Fig. 13 showing the auxiliary trunk group preference relays;

Fig. 14 showing the auxiliary marker preference relays;

Fig. .15 showing additional connectors; and

Fig. 16 shows the arrangement of Figs. 1 to 15, inclusive.

The trunk circuit of Figs. 1 to 3 is disclosed in applicants copending application, Serial No. 717,519, filed December 20, 1946, issued U. S. Patent No. 2,465,539, March 29, 1949.

Briefly, the operation of the circuit is as follows: After a call is extended to a trunk, the wanted line number is registered on registers individual to the trunk, When the last digit has been registered, the trunk operates the associated relay in the trunk preference chain of Fig. 4, where it competes with other trunks of the same group,operating a group-relay. The'group relay operates the relay associated with its trunkgroup in the preference chain at the top of Fig. 9 competing with other trunk-groups appearing in this connector. When a trunk group preference relay becomes effective the multicontact trunk group relay is operated'and a circuit prepared for operating a marker preference relay in the preference chain at the bottom of Fig. 9, where this connector competes with other connectors for an idle marker. 'The operation of a marker preference relay seizes the associated marker for this connector and operates the marker multicontact relay. With the trunk group and marker multicontact relays operated the registration transfer circuits areextended from the marker to the trunk group and a relay individual to the calling trunk is operatedto transfer the registration to the marker.

If there is undue delay in reaching a marker, the connectorj operates a relay in the connector preference chain of Fig. 10 where it competes with other connectors for the use of the auxiliary trunk group and marker preference relays of Figs. 13 and 14. When .a connector preference relay. becomes effective it disconnects the regular trunk group and marker preference relays and connects with the auxiliary preference relays which func-' tion with the associated connector to establish trunk-marker connections therein. Associated with the auxiliary preference relays are sets of preference advance relays which are operated to advance the initial preference after each use.

Detailed operation When the subscriber substation 100 originates a call, his line is associated with equipment at the Originating oflice indicated at 101 which responds to the dialing of the digits representing the ofice at which the wanted line is located, to extend the line to a trunk outgoing to that office. Assuming that the trunk of Figs. 1 and 2'hasib'eenrselected, a circuit is thereupon completed from battery through the lower winding of relay I06, conductor H9, contact 1 of relay 105, contact 1 of relay 10'4', tip conductor 102 to the originating office and the dialing bridge supplied thereat either 'bythe'oflice equipment or the calling line, ring conductor 103, contact 6 of relay I04, contact '4 of'relay 105', conductor 121, to ground through-the upper winding of relay 106.

Relay 106 operates in this circuit, closing an obvious circuit for relay 101 which alsooperates.

When the first digit of the wanted number is dialed, relay 106 releases at each openingoflits circuit, opening the circuit of relay 101. However, relay 10'1, being slow to release, remains operated throughout the dialing of the various digits. At its back contact, relay 106 completes az-pulsing circuit leading to the registercircuit of Fig. 3, which may be traced from ground at'the back contact of relay 106, contact I of :relay 101, contact 13 of relay I09, conductor 111, contact of relay 300, normal contact 341 of register 340, conductor 305, winding of relay. 302 and battery, and in parallel with :relay 302 'over'contact 1 of relay 301, normal contact 321 of register 320 to the winding of magnet314 -and battery.

Relay 302 operates in response to the first pulse and, being slow to release remains operated until the end of the digit. Magnet 314 responds to each pulse andadvancesregister 310 to a position corresponding to .the digit .dialed. When register 310 advances from normal it closes off-normal contact 313.

With relay 302 operated,,a circuit is closed (from battery through the winding of relay 304, b ack contact of relay 303, contact J-of relay-300, contact 3 of relay 301, contact 2 ofrelay 302, contact 5 of relay 101, and contact of relay 109. to ground over conductor -1 10. Relay304opcrates in this circuit closing a locking circuit for itself extending as above tracedto contact 3 'of relay 301 and thence over contact 2 of .relay 304 to ground on conductor 1 After the end of the digit, relay operated long enough for relay 302 to release and close a circuit from battery through the winding of relay 301, contact 5 of relay 301, contact 1 of relay 304, contact 1 of relay 302, contact 2 of 'relay 304 to ground on conductor 0. 'Relay L301 operates in this circuit, closing a locking circuit for itself over its contact 6, contact 2 of re1ay30'4 to conductor 110. At its mak'e-b'efore-brealk contacts 3 and 4, relay 301 closes an alternate holding circuit for relay 304 and then opens the previously traced holding circuit for that relay. This alternate holding circuit extends over the path traced for the original holding circuit to the make-before-break contact of relay 301, 'overthe make contact 4, contact 1 of 'relay'3'04, contact 1 of relay 302, contact 2 of relay-304'to ground on conductor 110. Therefore, both relays 301 and 304 are operated at the beginning of the second digit.

- The first pulse of the second digit :causes the operation of relay 302 as before, but the-pulsing circuit now extends from conductor- 305 overtcontact 2 of relay 301, normal contact .331 of register .106 remains vto ground on conductor 110. At the end of the digit, relay 302 releases in turn releasing relay 301.

The third and fourth digits are registered on registers 330 and 340 in substantially the same manner, except that relay 301, which is operated during the reception of the fourth digit by registe'r 340, closes at its contact 1 a substitute for normal contact 341 which opens as soon as register 340 steps off normal.

When relay 302 releases at the end of the fourth digit, a start circuit is closed for the marker connector which may be traced from ground on off-normal contact 343, contact '9 of relay 300, contact 3 of relay 302, conductor 361 to the winding of the trunk preference relay 402.

There is a trunk preference relay for each trunk served by the marker connector of Figs. 4 to 15. These relays are arranged in a plurality of groups, the relays of each group being ar ranged in a preference chain to prevent interference between trunks if more than one signal for connection with a marker at the same time. The trunk of Figs. 1 to 3 has been shown as .an intermediate trunk in the first group 400. Therefore, the circuit of relay 402 may be extended to battery only if the preference relays of trunks with the earlier preference relays are normal. If any of these trunks have closed their start circuits, the relay with the earliest preference will operate and the remaining relays wait their turn.

Assuming that no other trunk preference relay is operated, the circuit of relay 432 will be extended to battery over contacts 5 of intermediate preference relays and relay 401 associated with the first trunk 380, of the group. Relay 402 operates, opening at contact 6 the battery supply of preference relays lower in the chain such as relay 403 associated with the last trunk'300. At contacts '1 and 9, relay 402 closes a locking circuit for itself from battery over contact '1, winding and contact 9 of relay 402, conductor 360, contact 9" of relay 300 to ground at off-normal contact 343. Relay 402, therefore, remains operated independent of the preference chain and independent of relay 302. At contact 8, relay 402 connects ground to conductor 110 to prevent release of the registers while the marker is connected with the trunk.

At contact 5, relay 402 closes a circuit from battery to ground through the Winding of the group relay 405. Relay 405 at contact 2 grounds conductor 409 to start a timing function which will be described hereinafter. At contact 1, relay 405 closes a group start circuit which maybe traced from battery, contact I of relay 405, lower normal contact of jack 406, contact 2 of re1ay'404, conductor 430, normal contact of relay 1100, con ductor 1120 to the winding of group preference relay 900. There is a group preference relay for each group of trunks served by the connector of Figs. 4 to 14 and, as in the case of the trunk-preference relays, they are arranged in a preference chain to prevent conflict between groups which may have trunks seeking a marker simultaneously. Therefore, the circuit ofrelay 900 extends over contacts 5 of intermediate relays including relay.9I individual to intermediate group M0 and of relay 920 individual to the last group 420. If none of these relays is operated, the circuit of relay 900 is completed to ground and the relay operates. Relay 900, in operating, locks to ground over'its contact 6. 'At contact I relay 900 opens the operating circuit of relay 104, the function of which will be described hereinafter. At contact 2, relay 900 closes a circuit for'the group multicontact relay 500, which circuit may be traced from ground over contact 2 of relay 900, conductor 90L contact of relay IIOI, conductor II2I, winding of multi-contact relay 500, conductor 50I, back contact of relay 805 to battery over conductor 430 as previously traced. Relay 500 operates in this circuit, looking over contact 39 to conductor 430 independent of relay 805. At contact 4 relay 500 connects ground to conductor 1l0, operating relay 105 for a purpose to be described later.

Relay 560, when operated, initiates the selection of an idle marker. To this end it extends battery from conductor 430 over its contact 38, conductor 502, contact I of relay 800, conductor 866, back contact of relay I20I, to conductor I220 and the upper armature of relay 36L The marker associated with relays 960 and 96I is first choice in this connector. Therefore, the start circuit traced to the armature of relay 96I extends over the back contact of relay 96I to the winding of relay 960 and thence to ground through contacts of relays corresponding to relay 960 in the other connectors.

Themarkers serve other trunks which appear in other connectors, different markers being first choice in diiferent connectors. Therefore, the contacts of the relays like relay 960 associated with the same marker are connected in a chain arrangement similar to the chain arrangement of the individual trunk preference relays. Such arrangements are well known in the art and no attempt has been made to disclose the details thereof.

As soon as relay 960 operates, it looks in a circuit from battery on conductor '502, contact of relay I200, conductor I221, contact 3 of relay 960, contact I of relay 96I, winding and contact 5 of relay 960 to ground at contact 5. It also closes a circuit from ground over its contact 2, conductor 962, back contact of relay I200, conductor I22! to the winding of multicontact relay 602 and battery. Relay 602, at contact 4 grounds conductor 1!!! to hold relay 105 operated. With relays 555 and 602 operated, a plurality of circuits are established connecting the group of trunks with marker 250. When relay 602 operates, it connects ground from the back contact of relay 805, conductor 603, contact 4| of relay 602, conductor I222, back contact of relay I20I, conductor 954 to the upper winding of relay 66I in shunt of battery. Later the marker connects ground to conductor 963 leading to the upper windings of all of the connector relays associated with marker 250 like relay 96!, operating all of these relays except relay 96I, which is shunted as above described in the connector over which the marker is serving a register, thereby indicating that the marker is busy to the other connectors. In addition the marker connects ground to conductor 6H1, over contact I0 of relay 602, conductor 6I I,-contact I0 of relay 500, conductor 505, contact 3 of relay 403 and contact 4 of, relay 503, contact II of relay 403 and the intermediate relays, contact I0 of relay 402, conductor 362 to ground through the windings of relays 303 and 20I in the associated trunk circuit.

-With relay 30 3 operated, ground is connected to. the conductors individual to the registers of Fig, 3 which are connected to the group conductors and over the contacts of relays 500 and .632 to the marker, where the marker registers are operated in accordance with the registration setup in the trunk and the marker proceeds to control the extension of the trunk to the wanted line. The functions of the trunk under the control of the marker are described in applicants previously identified copending application.

While the marker is operating it connects ground to conductor 606, completing a circuit over contact 6 of relay 602, conductor 609, contact 3 of relay 500, conductor 504, lower winding of relay $04 and battery. Relay 404 when operated disconnects battery supplied by relay 405 from conductor 430, opening the operating circuit of relay 500. However, prior to operating relay 504, the marker connects battery to conductor 6i 2 closing a substitute holding circuit for relay 560 which becomes efiective when relay 455 operates and may be traced from conductor 6l2 over contact 36 of relay 602, conductor 801, contact 4 of relay802, conductor 506, contact 31 of relay 500, conductor 432, contact 3 of relay 405 to conductor 430 and thence to relay 900 as previously traced. The purpose of relay 404 will be described hereinafter.

When the marker has completed its functions, it grounds conductor 606, completing a circuit over contact 35 of relay 602, conductor 601, contact 36 of relay 500, conductor 363, lowermost contact of relay 303, conductor 364, winding of relay I09 and battery. Relay I09 establishes the talking circuit through the trunk and looks over its contact 8 to ground at contact 2 of relay I01 thereby signaling the marker that the trunk has been closed. It also closes a circuit from ground at its contact I5, conductor II3, over the oil'- normal contacts 3I3, 323 and 333 to battery through the left winding of relay 300.

The marker responds to the trunk closure signal by removing battery from conductor 604, permitting relays 303 and 20I to release. With relay 303 released and relay 300 operated, relay 304 is operated and circuits are closed for release magnets M5, 325, 335 and 345 to restore the registers to normal, after which relays 300 and 304 release.

The release of relay 20I connects the trunk conductors through to the switches 252, permitting the called line to be signaled and conversaltion to take place following response by the called The operation of the register release relay 300, opens the start and holding circuits for relay 402 and that relay releases, restoring the trunk perference chain to normal and releasing relays 405, 500, 300, 960 and 602.

While relay 402 was operated, one or more relays earlier in the trunk preference chain may have operated, and be in condition to connect with a marker. However, in order to insure a more equitable distribution of markers to trunks,

II of relay 602,

anti-ew as Well as the holding cirhuitfi -for relay -ifno other" unkpi ei'ere'n'ce relalys "are one ed,'relay 48'4 rid aqafl reiea'se I-f anothertr-i-inl referenee rel"yisoperated for 'example, relay lIIlIg relay-M05 i by battery-rover: contact 5- Q'f relay -AIJIt If a tru iik inzanether greup is waiting for connection to a marker; the I associated.- group-preference relayifor exanfple; relay 320 will becperated; hold inelorifi p eu f r 'r 5titothe'lowerwinding ofrelay 8M-andbattery;

Therefore: althoughtheoperatirig circuit for relay 4fl4 -has ben openedi that relay "will be heldlocked in a circuit fror'n battery over-contact I cf -relayz-lfl'd', lower nei'malcontact of-jack 496,

contact -4 anduppei wi'n'clirig of relay w i, con

meter: 43l to ground at contact-'3 0f relay 194-. When oi ie 't 'rik 'in the: group--a'ssociated with reiay 920 has been" coniiectedwith a marker, relay Sm le-released 'and-the operati'ng circuit fen-relay "1M=rec1osed toopen the locking circuit for= relay"404 thereby restoring-the operating ci-rcuit for group relay-9B0. If calls ar waiting in a plurality 1 oi groups); the relay 1 corresponding to relay 4% in each group is locked"until all waitin'g' groups have' had onetru'nl: served, at

will noted that -relay w l -is slow to 'release,

to prevent its release during the intrval between 45 the=associated tiriiing circuit complets it s operation-igrdund is connected troublerelease conductor 6 I 3, thereby "completing-a circuit over contact iifi 'ofrela y conductor" 8 I 4; contact I of' rel'ay 833 winding of relay 892 and battery.

Relaytfi'icloses a locking circuit'fforit's'elf through '55 the winding 01" relay-ate; contact 2""of"relay '802, conductor 813 to ground at'contactfi of relay BBDJ Relay 80 3 dosnbt cp'erat at" this time' being shunted by the-operating *circuitf'or'relay 802.

With relay 882 operated the circuit over which 0' battery was supplied from' the rriar'ke'r'to hold relay- 91m is rern'oyedfbilt conductor 506 is extendedbvercontact '3 "of relay 802 to battery at contact "lofrelay liiwfpreventingthe release of relay 9119. At contact I, h obvious circuit tar); relay "BB5" whiclibperates, removing the shunt *fr mtl'ie battery supplied to relay 98F"therebyfipermittihg relay 96I topperate and mark'the-marker busy 'intlfii's channel.

With relay SEI operatedf'relay 96 0" releases, in

turn releasing 'r'eI'ayBM'. If any other marker is idle; relayf 96 I locks 'iri a circuit from battery through-its lower: winding and contact 3 contact 3 -of =the' relay.-like 96I 'associait'ed witli an "idle I circuit icerelay Bill-and permits -rela'yWflB -t conneet'sground te conductor 603 to shunt the held operated 0 relay 802 closes an 65 op cr ate in the locking circuit previously trace since relay 905 is held operated, -tl ie operati' of relay 96! transfers the marker start circuit' to the next preference relay ass'oc'i'ated'with an idle ii niarker and-brihgs-abdut-the connection of that marker with -the trunk'to makea second tri'alt" Ifthere are no idle-markers,- relay 96l can'ndt'lock and the "same marker may be selected for" the second trial; Relay 803, operated; at contact busy-relay corresponding to relay 9H belonging tothe new marker; At contact! {relay tea e05 nects ground over conductor 889; contact-39 01 Q the multi-conta-ct relay of-the newly selectedmarker and conductor 61 5' leading" thereto, in

f orrningtha-t marker that it is making "a second trial: These'eo'nd trial- -m'arlrer grounds conduc-" tor S56, completing a circuit over contact 46"0f" the 'corre'sponding multicontact relay; conductor With"relay-iifi toperated, conductors 50'6'and BB1, whichw'ere disconnected'by the operationofrelay Effi- "are "again "connected together "to reclosethe holding circuit'for relay 1900;

If'the second marker completes the connection;- it disconnects battery irorn'conductor 6 I2 ,'-re1'ea ing rela'y'sallfl, 5G0; 602 and-"in turn "relays 802'," 883 ar1 d"'8il5. As'soo'n asrelay -9B'Ureleases, a tr'i'irik'group which is waiting is inpositionto operate *its multicontacfirelay, but cannot do" so until relay 865 releases, in order to insure'Whe releasefof the secondtria'l relays. A

If the second trial. marker" also encounters trouble and grounds" its conductor 6 I3, thereby grounding' 'conductor GM'in'the connector," aicircuit'wouldbe' completed overcontact 2of relay 8%;up'per winding "of relay 804" to battery and iiiparallel with the winding of relay 804 over condiictdr 8 I 0, contact All of relay 500, conductor 501, contactI'bfrelayflM, contact"! of relay'403, and" the intermediate trunk preference relays, con tact"; of"r'e1ay 4e12,? onductor 361' to the right wiii'diii'g'bf relay 30Iland battery 'to'bring' about the release of the trunk re'gistersand to transmitian overflow sigrial over the'incomin'g trunk, as'fdesc'ribed fina'pplicants above-identified coendihgap lieatifon'.

If conductor- 8'fiflor'8lll shoul'd become falsely grounded "inthe'conriec'tor multiple, trunk reg- *isterci'r'cuits would repeatedly'be dismissed pre-i maturely' or be handled on. a second trial basis by the marker." Therefore; theseco'riductors are tested duringithe 'tiiife that the connector circuit is idle.' ,As above mentioned, with either'a-trunk'" register multicontact'relay, like re1a'y 500, or a. marker multicontactirel'ay lilie'relay 602 operated; relay 105 is heIdLQp'e'ratedu When nonevof thev multicontact relaysfis. operated, relay 105 is re-. lease'danda false groundnn' conductor 809 would complete a circuit over contact 5 of relay.803, contact I of relay'lll5flower winding of relay I08 andbattery. Similarly, a false ground on conductor 8Ill would complete a circuit over contact" 3 o f 'relay '1Il5, contact 2 andiupper" winding, of relay "(00 to battery. Ineithencase relay 100 locks togro'und over conductor "HI, sets up an indication"overconductor*1I3 of the identity of the container circuit wmcri is in" trouble "and sour-id's' afi'alarfn"over conductofl I23 Relay 101i 5 marker;v conductor 965, 11 bacli' -contact 'of relay also ioperates' if gfuiidwippears dfi w f43 3'b.

or 434 which might indicate a cross-connection within the trunk preference relay chain capable of affecting more than one trunk circuit.

As mentioned above, relay 405 is operated as long as one of the trunk preference relays is operated and relay 104 is released whenever one of the group preference relays is operated. With relay 405 operated or relay 104 released ground is connected to conductor 409 and over contact I of relay 103 to conductor 109 extending to the interrupter 120. Conductor 109 is also grounded over contact 4 of relay 103, conductor 508 and contact 2 of relay 500 or other trunk group multicontact relay. With conductor 109 grounded, relay 106 operates over the left contact of interrupter 120 and locks to conductor 109. A measured interval later relay 102 operates over the right contacts of interrupter 120 and relay 106 and extends its operating ground to the upper winding of relay I which operates, locks itself and relay 102 to conductor 109 and locks inde: pendent of relay 102, over its contact 5 and conductor 1I6 to a key at the trouble indicator frame. When relay 802 or other marker multicontact relay operates, ground is connected over contact 2 of that relay to conductor 6J8, operating relay 103 and disconnecting conductor 109 from conductors 409 and 508, releasing relay 106 if operated. Ground on conductor 6l8 alsoextends to interrupter 12 I operating relay 101 when the left contact is closed. Relay 101 locks to conductor 6I8 and when after a measured interval the right contact of interrupter 12I closes, com- 'pletes a circuit through the upper Winding of relay 102 which locks to conductor 6I8. The operation of the connector is therefore divided into two timing intervals, shortening the time that must elapse before an alarm isv sounded. Relay 102 when operated connects ground to conductor 1I2 to start the alarm circuit andrelays 10I, 102 and 103 all ground conductor 1I3, to identifythe connector.

Since the operation of relay 10I indicates a failure to seize a marker it is used to start the connection of the associated connector with'the' auxiliary preference relays of Figs. 10, 13 and 14. With relay 10I' operated, a circuit is closed from battery through resistance 108, contact I of re-] lay 104 or contact 3 of relay 405, conductor I020, contact I of relay 10I, conductor 1I4 to the winding of the connector preference relay I 000 and ground. Each of the connectors on the same frame has such a preference relay and they are connected in a chain arrangement similar to that of the trunk preference relays so that only one connector may use the emergency preference re-, lays at a time.

Relay I 000 has the preferred position for operation and operates whenever its circuit is closed and looks over its contact I, conductor, I020, contact I of relay 104 or contact 3 of relay 405 to battery through resistance 100. At contact 3 relay I000 connects ground over the upper normal contact of jack IOI I and contacts 2 of the other connector preference relays, such as relays I002 and NIH, associated with connectors I500 and I 50I, contact 3 of relay I000 to conductor I'02I to indicate that the preferencerelays are in use. At contact 5 it opens the operating circuit for the connector preference relays having less favored positions in the preference chain. At contact I I it closes a circuit from ground over the lower normal contact of Jack IOI I, contactfi of' relay l0 I0, contacts I0 of relays I002; I00 I ,-etc'.;,' contact I I of relay I000, conductor I022 to bat winding of relay I322 and tery through the windings of disconnect relays H00, IIOI, II02, I200 and I20I in parallel. These relays operate, disconnecting the connector cir-P cuit from the regular group preference relays and the regular marker preference relays, opening the circuits for the trunk group multicontact'-relays When the operated multicontact relay releasesI it opens the circuit of relay and that relay releases. v 1

As soon as relay 105 closes its contact 2, acircult is closed from battery through windings of the cut-in relays IIIO, IIII, III2, I2I0, I2 and I2I2 in parallel, front contacts of relays I20I, I200, II02, HM and H00 in series, conductor H24, contact 2 of relay 105, conductor 1I5, con tact 9 of relay I 000, contacts I0 of relays IO0I', I002, etc., contact 3 ofrelay IOI0, lower normal contact of jack IOII to ground. Relays IIIO, IIII, III2, I2I0, I2 and I2I2 connect the con, nector circuit with the auxiliary preference relays;

The auxiliary preference relays consist of a duplicate set of trunk group preference relays, I300 to I302 and a duplicate set of marker pre'ference and connector busy relays I400, I 4I0, I420 and HM, I4 and I42I. In addition, there is provided two sets of preference advance relays I3I0 to I3I2 and I402, I4I2 and I422, arranged to change the order of preference on the trunk' group preference relays and the marker preference relays on each call and on the marker preference relays whenever a second trial is made. Relay I000 in operating at contacts I2 and .4 grounds conductors I023 and I024 to provide locking ground for these preference advance relays.

Relays IIIO to III2 and I2I0 to I2I2 each con nect ground to conductor 1I1 providing a locking circuit for the disconnect relays over the} upper front contact of relay I I00 and an operat: ing circuit for relay IOI0 over the contact 8 of relay I2I2 and conductor I223. Relay I 0| 0 opens the operating circuits for the disconnect and cut-' in relays, connects ground to conductors I 023 and- I 024 and closes a locking circuit for the cut-inrelays which extends from the winding of these. relays over contact 5 of relay I 2| 2, conductor I224, contact 1 of relay I000, contact 8 of relays} IO0I, I002, etc., contact 4 of relay IOIOI't'oL ground over the lower normal contact of jack. IOI I. The operation of the cut-in relays of this connector is therefore maintained as long as relay 405 remains operated.

With relay IIIO operated, battery on conductor 430 is extended over conductor I I25 to the. winding of relay I300 and ground at a back contact of relay I322. Relay I300 operates inthis circuit and locks to ground over its contact 5. At' contact I it opens the normally closed chain circuit to relay 104, causing that relay to release and connect battery through resistance 108.to. conductor I020 to hold relay I 000 operated. At contact 2, relay I300 closes a circuit from ground over contacts I of relays I302, I'30I, etc., contact. 2. of relay I300, conductor I323, contact 2 of re lay I32I to the winding of relay I320 and bate; tery. Relay I32I closes a circuit from ground on conductor I323, over contact 2 of relay I320. to the winding of relay I32I and battery. Relay-g- I32I looks over its contact 3 to conductor I323, opening at contact 2 the operating circuit for f rela I320 which releases. With relay I 320 re-' leased a circuit is closed fromground overcontact; Ioijrelay I 32I, contact I of relay I320 to the; a t ope i re...

lay I322 to remove ground from the windings of" 

